红树林水生动物栖息地功能及其渔业价值

The habitat functions of mangroves for aquatic fauna and fisheries

红树林生长于热带、亚热带海陆交界的生态敏感带,其根系为生活于潮间带高度异质环境下的生物提供了适宜生境:藻类、双壳类、甲壳类等大量附生于红树根部;红树的呼吸根、支柱根、树干、倒落的枝条和残骸等,与沉积物形成的松软基质为大量底栖动物提供栖息地,根部结构间的空隙成为虾类、蟹类和鱼类等游泳动物的优良避难所和索饵场。红树林凋落物以碎屑形式进入食物网,连同浮游植物、附生藻类和底栖微藻等,是红树林生态系统的碳循环重要组成部分,为红树林区水生动物提供了丰富的食物来源。可见,食物来源丰富、隐蔽性强、捕食压力低等特点使得红树林成为水生动物的理想栖息地,许多水生动物选择在其中度过部分或完整生活史。另外,红树林也是重要经济动物(鱼、虾、蟹类)的育苗场,为近岸鱼类种群的补充和渔业活动提供支持。为合理开发红树林区渔业和有效保护红树林湿地生态系统,从生境价值、凋落物在红树林生态系统食物网中的贡献等方面总结了红树林栖息地功能及其渔业价值,提出今后的研究方向应将红树林的栖息地功能从其它河口、近岸栖息地中分离出来,甄别不同栖息地间的动态关系及其对渔业的影响。

Mangroves grow mainly in the ecologically sensitive zones between land and sea in the tropical and subtropical regions.The root system of mangroves provides a suitable substratum in which many species of organisms thrive.The mangrove roots are overgrown by epibionts such as algae,bivalves and crustaceans,etc.The soft substratum in the complex structure provided by pneumatophores,proproots,trunks,fallen branches and detritus forms habitat for various benthic species.And the space between roots provides shelter and food for motile fauna such as prawns,crabs and fishes.Leaf litter of mangrove is transformed into detritus,which is part of the mangrove food web along with plankton,epiphytic algae and microphytobenthos.By providing a high abundance of food and shelter,and low predation pressure,mangroves form an ideal habitat for a variety of aquatic animals,during part or all of their life cycles.Similarly,mangroves may function as nursery habitats for commercially important crab,prawn and fish species,and support offshore fish populations and fisheries.For the development of sustained fishery and conservation of the mangrove ecosystem,we reviewed the habitat functions of mangroves for aquatic fauna and fisheries including the habitat values of mangrove ecosystems and the importance of litter in the mangrove food web.Future researches should be focused on separating the roles of mangroves from those of estuaries and other offshore habitats,and investigating the effect of the dynamic relationship between different habitats on fisheries.